This class is intended to be a central place for the jdk to log timing events of interest. There is pre-defined event of startTime, as well as a general mechanism of setting arbitrary times in an array. All unreserved times in the array can be used by callers in application-defined situations. The caller is responsible for setting and getting all times and for doing whatever analysis is interesting; this class is merely a central container for those timing values.

To automatically track startup performance in an app use the command-line parameter sun.perflog as follows:

-Dsun.perflog[=file:<filename>]

where simply using the parameter with no value will enable output to the console and a value of "file:<filename>" will cause that given filename to be created and used for all output.

By default, times are measured using System.currentTimeMillis(). To use System.nanoTime() instead, add the command-line parameter:
-Dsun.perflog.nano=true

Warning: Use at your own risk! This class is intended for internal testing purposes only and may be removed at any time. More permanent monitoring and profiling APIs are expected to be developed for future releases and this class will cease to exist once those APIs are in place.

Modifier and Type	Class and Description
pack-priv static class	PerformanceLogger.TimeData Internal class used to store time/message data together.

Field Summary

Modifier and Type	Field and Description
private static long	baseTime
private static final int	LAST_RESERVED
private static String	logFileName
private static Writer	logWriter
private static boolean	perfLoggingOn
private static final int	START_INDEX
private static Vector<PerformanceLogger.TimeData>	times
private static boolean	useNanoTime

Constructor Summary

Access	Constructor and Description
public	PerformanceLogger()

Method Summary

Modifier and Type	Method and Description
private static long	getCurrentTime() Return the current time, in millis or nanos as appropriate
public static String	getMessageAtIndex(int index) Returns message at given index.
public static long	getStartTime() Gets the start time, which should be the time when the java process started, prior to the VM actually being loaded.
public static long	getTimeAtIndex(int index) Returns time at given index.
public static boolean	loggingEnabled() Returns status of whether logging is enabled or not.
public static void	outputLog(Writer writer) Outputs all data to parameter-specified Writer object
public static void	outputLog() Outputs all data to whatever location the user specified via sun.perflog command-line parameter.
public static void	setBaseTime(long time) Sets the base time, output can then be displayed as offsets from the base time;.
public static void	setStartTime(String message) Sets the start time.
public static void	setStartTime(String message, long time) Sets the start time.
public static int	setTime(String message) Sets the value of a given time and returns the index of the slot that that time was stored in.
public static int	setTime(String message, long time) Sets the value of a given time and returns the index of the slot that that time was stored in. This version of the method is given the time to log, instead of expecting this method to get the time itself.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

baseTime	back to summary
private static long baseTime

LAST_RESERVED	back to summary
private static final int LAST_RESERVED

logFileName	back to summary
private static String logFileName

logWriter	back to summary
private static Writer logWriter

perfLoggingOn	back to summary
private static boolean perfLoggingOn

START_INDEX	back to summary
private static final int START_INDEX

times	back to summary
private static Vector<PerformanceLogger.TimeData> times

useNanoTime	back to summary
private static boolean useNanoTime

Constructor Detail

PerformanceLogger	back to summary
public PerformanceLogger()

Method Detail

getCurrentTime	back to summary
private static long getCurrentTime() Return the current time, in millis or nanos as appropriate

getMessageAtIndex	back to summary
public static String getMessageAtIndex(int index) Returns message at given index.

getStartTime	back to summary
public static long getStartTime() Gets the start time, which should be the time when the java process started, prior to the VM actually being loaded.

getTimeAtIndex	back to summary
public static long getTimeAtIndex(int index) Returns time at given index.

loggingEnabled	back to summary
public static boolean loggingEnabled() Returns status of whether logging is enabled or not. This is provided as a convenience method.

outputLog	back to summary
public static void outputLog(Writer writer) Outputs all data to parameter-specified Writer object

outputLog	back to summary
public static void outputLog() Outputs all data to whatever location the user specified via sun.perflog command-line parameter.

setBaseTime	back to summary
public static void setBaseTime(long time) Sets the base time, output can then be displayed as offsets from the base time;.

setStartTime	back to summary
public static void setStartTime(String message) Sets the start time. Ideally, this is the earliest time available during the startup of an application. This time is later used to analyze the difference between the initial startup time and other events in the system.

setStartTime	back to summary
public static void setStartTime(String message, long time) Sets the start time. This version of the method is given the time to log, instead of expecting this method to get the time itself. This is done in case the time was recorded much earlier than this method was called.

setTime	back to summary
public static int setTime(String message) Sets the value of a given time and returns the index of the slot that that time was stored in.

setTime	back to summary
public static int setTime(String message, long time) Sets the value of a given time and returns the index of the slot that that time was stored in. This version of the method is given the time to log, instead of expecting this method to get the time itself. This is done in case the time was recorded much earlier than this method was called.

sun.awt.util back to summary

pack-priv Class PerformanceLogger.TimeData

Class Inheritance

extends Object

java.lang.Object
sun.awt.util.PerformanceLogger.TimeData

Internal class used to store time/message data together.

Field Summary

Modifier and Type	Field and Description
pack-priv String	message
pack-priv long	time

Constructor Summary

Access	Constructor and Description
pack-priv	TimeData(String message, long time)

Method Summary

Modifier and Type	Method and Description
pack-priv String	getMessage()
pack-priv long	getTime()

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

message	back to summary
pack-priv String message

time	back to summary
pack-priv long time

Constructor Detail

TimeData	back to summary
pack-priv TimeData(String message, long time)

Method Detail

getMessage	back to summary
pack-priv String getMessage()

getTime	back to summary
pack-priv long getTime()

public Class PerformanceLogger

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

pack-priv Class PerformanceLogger.TimeData

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail